Birds and planes have been colliding(碰撞) since the Wright brothers(莱特兄弟，飞机发明者) first took to the air.
There are dozens of bird strikes each day, causing hundreds of millions of dollars in damage to airplanes each year, and putting the lives of passengers and crew members(乘务员) at risk. Researchers at Cornell Lab of Ornithology are now working on a way to help prevent collisions(碰撞), by deciphering(破译) the calls birds use to communicate on their migration(迁移，迁徙) routes.
There's more to the language of birds than songs. They also use short calls - less than a second long. And each species speaks its own language.
Ken Rosenberg has been an avid(渴望的) bird-watcher since he was a boy. Today he works at the Cornell Lab of Ornithology, unraveling(拆开) avian(鸟类的) mysteries. He says that birds use these short calls most often during migration.
Until recently scientists weren't aware of the extent of these calls, because most bird migration takes place at night.
"It really began with amateur(业余的) bird watchers who were noticing these sounds in the sky and knew that they were birds migrating overhead. But a few people became detectives and tried to figure out what these calls were of all the different birds."
The migratory flyways over the United States are crowded with billions of birds every spring and fall.
By aiming special microphones at the night sky during these times and recording the passing calls, scientists realized they could determine the kinds of birds that were flying overhead, and learn their migration schedules(时间表) and flight paths. But there was a lot of sky to cover.
Pat Leonard, also with the lab, says they turned to military bases(军事基地) and amateur birders(猎鸟者) to help record the sounds. "We couldn't do that any other way if we didn't have everyday birders out there collecting that information for us. There are just too many birds and too many places."
And maybe too much data. Each location recorded eight hours worth of tape nightly, all of which had to be listened to in real time. And many of these short calls sound very similar to the untrained ear.
That’s recording of the calls of 48 different types of thrushes(画眉鸟). The Ornithology Lab teamed up with(与……合作) Cornell University's Bioacoustic Research Program to develop software that would decode(解码) the birdcalls.
The program can isolate(分离，隔离) the unique characteristics of each thrush species into algorithms(算法) much like voice recognition software. After processing, individual calls become more pronounced(显著的).
"It still may always take a human to review the results, but it should eliminate all the steps of having to sit and listen and watch the thing go by on the screen."
That means more researchers can work on night flight call projects more quickly. That data should reveal what species are flying where and when.